An appeals court ruled a Kane County sergeant improperly prolonged a traffic stop from which authorities seized a car and more than $8,000 cash, and now the driver and passengers are suing the county and officers involved in federal court.

The officer who initiated the stop once described asset forfeiture as "a tax-liberating gold mine" that allows the government to "pull in expendable cash hand over fist," according to a complaint filed in U.S. District Court. The officer, a sergeant, also works for Desert Snow, a private company that trains officers in police stops and asset forfeiture, according to the lawsuit. The Kane County sheriff's office is among agencies that have paid Desert Snow for training.

Kane County Sheriff spokesman Lt. Patrick Gengler said it appears the county has sent 10 deputies to Desert Snow training and paid the company less than $5,000.

Hain's work with Desert Snow was initially approved under former Sheriff Pat Perez, Gengler said.

The sheriff's office has taken in millions of dollars of cash and assets from forfeiture carried out by Hain and other employees during hundreds of traffic stops, according to the complaint.

After Hain pulled over a black Chevrolet Impala with Minnesota plates on Interstate 90 at Route 47 and issued a warning during that 2015 stop, police searched the vehicle and found a 9mm bullet, marijuana flakes, a Ruger handgun with one bullet in the chamber, another handgun loaded with a bullet in the chamber, an $8,000 cash bundle stowed inside a purse and a backpack containing a plastic bag with 400 grams of uncut heroin inside.

Jessica Johnson, Derek Paddy and Leo Cook were arrested and taken to the sheriff's office, where they refused to provide statements and asked for a lawyer, according to reports.

Felony charges were filed against the three including possession of heroin with intent to deliver and armed violence. Their cases are pending in Kane County court.

The lawsuit contends the officers lacked legal justification to extend the duration of the traffic stop after Hain completed the warning.

The officers also didn't have the right to question the passengers, order them out of the car or take them or Johnson into custody, have the dog sniff the car, search the car, or seize any of the money, the lawsuit states.